View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *   http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing,
13   * software distributed under the License is distributed on an
14   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   * KIND, either express or implied.  See the License for the
16   * specific language governing permissions and limitations
17   * under the License.
18   */
19  
20  package org.apache.myfaces.orchestra.viewController;
21  
22  import org.apache.myfaces.orchestra.lib.OrchestraException;
23  
24  import java.lang.reflect.InvocationTargetException;
25  import java.lang.reflect.Method;
26  
27  /**
28   * Invokes ViewController events using reflection.
29   * <p>
30   * If the target bean has a method with any of the following signatures then it
31   * receives the appropriate callback:
32   * <ul>
33   * <li>public void initView()</li>
34   * <li>public void preProcess()</li>
35   * <li>public void preRenderView()</li>
36   * </ul>
37   * <p>
38   * Note that each method here returns false if the target bean does not
39   * have a method with an appropriate signature; this allows this executor to 
40   * be "chained" with others.
41   */
42  public class ReflectiveViewControllerExecutor extends AbstractViewControllerExecutor
43  {
44      /**
45       * Helper method to find the method which should get invoked.
46       */
47      protected boolean invokeOnViewController(Object bean, String methodName)
48      {
49          try
50          {
51              Method method = bean.getClass().getMethod(methodName, (Class[]) null); // NON-NLS
52              method.invoke(bean, (Object[]) null);
53          }
54          catch (NoSuchMethodException e)
55          {
56              return false;
57          }
58          catch (IllegalAccessException e)
59          {
60              throw new OrchestraException(e);
61          }
62          catch (InvocationTargetException e)
63          {
64              throw new OrchestraException(e);
65          }
66  
67          return true;
68      }
69  
70      /* the ViewControllerExecutor interface */ 
71      public boolean invokeInitView(String beanName, Object bean)
72      {
73          return invokeOnViewController(bean, "initView");
74      }
75  
76      public boolean invokePreRenderView(String beanName, Object bean)
77      {
78          return invokeOnViewController(bean, "preRenderView");
79      }
80  
81      public boolean invokePreProcess(String beanName, Object bean)
82      {
83          return invokeOnViewController(bean, "preProcess");
84      }
85  }